2020-05-04
If you are on Windows XP or Vista, you can safely use CCleaner version 5.64, please download our slim build here (https://www.ccleaner.com/ccleaner/download/portable?os=5.1w3).
This version will only ever receive critical security updates.
 => https://support.piriform.com/hc/en-us/articles/360040325231-Which-versions-of-CCleaner-work-with-Windows-XP-or-Vista-
 => https://support.piriform.com/hc/en-us/articles/360040324931-Why-do-you-no-longer-support-Windows-XP-or-Vista-

Note: v5.27+ requires the system hardware to support SSE2. If your hardware is too old, v5.26.5937 is the latest working release.